Tire-pressure gauge



`Ian. 7, 1930. A, WATTERS 1,742,740

TIREl ERES SURE GAUGE Filed Jan. 9. 1,920

375g, 9,2% #LZ2-MQ? WM@ Ai=0 receiving the end of the tire va ve.

Patented Jan. 7, 1930 UNITED STATES .ALEX WATTERS, F CHICAGO, ILLINOISrmn-rnnssrrnn GAUGE Application led January 9, 1920. Serial No. 350,894.

This invention relates to testers or tire gauges such as used fortesting the compression of the air in pneumatic tires.

The principal object of this inventionis to provide a tester or .gaugeof particularly simple construction and 011ev which will be exceedinglyaccurate in operation. Other objects are to provide a device of thischaracter in which the principal elements may be drawn or stamped; toprovide a tester having few parts; to provide a tester having anindicating gauge which will remain in adjusted position when theindication is made; to provide means for adjustment of the gauge, and toprovide a gauge or tester having such novel features and such advantagesas will be more fully apparent from the following description taken inconnection with the accompanying drawings. In these drawings:

Fig. 1 is a side view; Fig. 2 is a longitudinal sectional view; Fig. 3is a top view; and, Fig. 4 is a bottom view. The tester comprises atubular body portion 5 which may be made of any suitable material and inany convenient manner but which is preferably drawn from sheet metal andisformed with one end or head 6 which has a hole therethrough for theindicating member. A plate or washer 7 fits over the open end of thecylinder 5 and has a projection 8 for engagement with the valve stem foropenin the tire valve. This head or end 7 is provided with a hole 9 toadmit an' to the cylinder. A. soft rubber washer 10 iits over theprojection 8 and rests against the washer 7. These washers are held inposition by a cap 11 which lits over the end of the cylinder 5 and whichhas a central o ening 12 for The cap 11 may be held by being forced ontothe cylinder or may be otherwise secured thereto. The cylinder 5 isprovided with a piston 13 which may' be made in any suitable manner butpreferably comprises a lower disk 14 and an u per disk 15 with aresilient washer 16 held between them. These parts are secured togetherby means of a rivet 17 The upper disk 15 is preferably shouldered asindicated at 18 for engagement with one end of a compression spring 19which extends from the piston to the head or end 6. The indicatingmember is formed of a strip of metal or resilient material bentl in asubstantially U- shape thereby forming two arms 20 and a cross-piece 21.This indicator extends in through thehole 22 in the end 6 and is adaptedto be actuated by the piston. The arms 20 have suiieient frictionalengagement with the sides of the hole sothat the indicator will be heldin adjusted position. In order to prevent the indicator from beingaccidentally displaced or removed from the cylinder, one of the arms 2()is provided with a notch 23 which will engage with the end 6 and preventthe outward movement of the indicator. However, the indicator may beremoved by pressing the arms 20 together a suilicient amount to releasethe catch. One or bot-h of the arms 20 is provided with an indicatingscale 24 for indicating the pressure on the piston.

It is diiieult to produce a plurality of springs all having the samecompression and after a spring has been used for some time, it is liableto become somewhat weakened. For this reason, I provide means foradjusting the indicator with relation to the piston and spring so thatit may be adjusted to give an accurate reading on the scale. In thepresent instance, this adjustment is provided by havin a screw 25 whichengages with the threa ed crossiece 21 and is provided with a locknut`26. T e head of the screw engages with the piston, preferabl withthe rivet 17. The reading of the scale 1s taken at the line where itrejects from the end of the cylinder and it wi l be readily seen thatthe screw may be regulated to bring the scale to re ister to show theproper readinlgl when the evice is tested in comparison wit a standardpressure gauge.

It wi Figs. 1 and 2 with the piston in raised position which it wouldassume when air under pressure is admitted to the cylinder.

When the air in a tire or'other receptacle is to be tested, the gau e ispressed down over the tire valve and t e resilient Washer 10 serves tomake a tight connection. The proll be noted that the device is shown injection 8 presses against the valve stem so as to admit air into thecylinder 5. The air pressing against the piston 13 tends to raise thesame against the pressure of the spring 19.

As the piston moves outwardly, the pressure may be determined by thegauge or scale 24 which is properly calibrated to correspond with thespring. When the tester or gauge is removed, thepiston will return tonormal lo position but the indicator will remain in raised or extendedposition to indicate the pressure. Forthis reason, the device may bereadily ap lied to a valve, even if the valve is in a dar place, and maythen be taken to the light to read the pressure. The indicator is thenBressed down against the piston for taking t e next reading.

Having thus described my invention, what I claim and desire to secure byLetters Pat m ent is: f c 1. In a tire (pressure gauge, the combinationof a cylin er having an air inlet at one v end, a piston in saidcylmder, a s ring tending to move the piston in one rection, a 25pressure indicating member engaging with said piston and projectingthrong t e end of the cylinder, means for holding the indieating memberin adjusted position, and an adjustable member secured to the indicatingso member and adapted to engage with the piston for adjusting theindicating member with respect to the piston. y

2. In an air ressure gauge, the combina-Y tion of a cylin er, a piston1n said c linder, as means for admittin air to one en of the cylinder, asubstantially U-shaped indicator extending out through a hole in theopposite end of the cylinder, and an adjusting screw in said indicatorfor engagement wlth the 40 piston.

3. In an air pressure gauge, the combination of a cylinder having apiston therein, an indicator comprising a strip of metal bent to formtwo arms with a crow-piece at one end,

said indicator extending out through an opening in the end of thecylinder, a stop on one of said arms adapted to en age with the end ofthe cylinder, and an adjusting screw in said cross-piece for engagementwith the so piston. j -v 4. A pressure gauge com rising a c linder havina iston sli able t erein an a detache indlcating member co-operatingwith said piston and a screw for adjusting the indicating memberrelative to the iston.

ALEX WA RS.

